Six New Species of Philine (Opisthobranchia: Philinidae) 
from the Tropical Indo-Pacific 
Claire Gonzales ^ and Terrence Gosliner ^ 
1 Biology Department, Duke University, Box 97567, Duke University, Durham, NC 27708, E-mail: CGonza- 
les@calacademy.org; ^Department qfinvertebrate Zoology, California Academy of Sciences, 55 Music Con¬ 
course Drive, San Francisco, CA 94118, U.S.A. E-mail: tgosliner@calacademy.org 
Six new species of philinid opisthobranchs are described from various localities in 
the tropical Indo-Pacific. Most were collected from deep waters of the Verde Island 
Passage, Philippines, while one additional species was collected from relatively shal¬ 
low water from Panglao, Philippines and the second from shallow water in the 
Hawaiian Islands. 
Morphological characters, including anatomical details of the shell, radular mor¬ 
phology, gizzard plates and male and hermaphroditic reproductive systems are 
entirely congruent with the molecular differences found. Four of these taxa are mem¬ 
bers of the Philine aperta clade, while two taxa are members of a more basal lineage. 
Philine acuticauda sp. nov. has an elongate body, has a large, smooth shell, lacks giz¬ 
zard plates and has a radula with two outer lateral teeth, the outer of which is 
reduced with a blunt cusp. Philine hearstorum sp. nov. is also elongate but has a 
series of clearly defined striations on the shell. It also possesses three small gizzard 
plates with a distinct crystalline structure, has two outer lateral radular teeth with 
prominent cusps. Philine dentiphallus sp. nov. has residual punctate sculpture lines 
on the shell, has three equally sized gizzard plates with a prominent medial bar 
above a single large depression. The radula has a single outer lateral tooth with a 
prominent cusp. The penis is hammer-shaped with a series of denticles on the outer 
lobe of the penial papilla. Philine verdensis sp. nov. has a large, smooth shell devoid 
of striation or other obvious sculpture. The gizzard plates are unequal with two larg¬ 
er plates and a single small plate, all with two prominent pores. The penial papilla is 
hammer-shaped with an unarmed papilla. Philine pittmani sp. nov. has unequal giz¬ 
zard plates where the two longer plates each have only a single pore, Philine multi- 
papillata sp. nov., has a smooth shell, devoid of obvious sculpture, has three unequal 
gizzard plates, all with two large prominent pores. The penis is complex, having a 
penial papilla densely armed with conical papillae over the entire surface. Tliis study 
reinforces the view that the diversity of the Indo-Pacific Philinacea still remains 
incompletely sampled including the Philine aperta clade. Philine acuticauda and 
P. hearstorum appear to be most closely related to P. alba and P. alboides and repre¬ 
sent the first representatives of this group known from the tropical Indo-Pacific. 
Both morphological and molecular data support the phylogenetic position of these 
taxa. The more basal members have small gizzard plates or entirely lack them and 
have a simple penis, while species in the Philine aperta clade have plates with pores 
or slits and have a complex penis and prostate. In sampling broader outgroup rela¬ 
tionships, some members of Philinidae cluster with species of Aglajidae, suggesting 
that Philinidae as traditionally constructed does not constitute a clade, but repre¬ 
sents a paraphyletic assemblage. These relationships need to be further studied with 
more extensive taxon sampling of philinaceans, but are suggestive that further sys¬ 
tematic revision is required to develop a classification consistent with the phytogeny 
of the Philinacea. 
Keywords: Philinidae, Philinacea, Indo-Pacific, new species, biodiversity 
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